Autofill shown should not update lastUsed

[GioSensation]

Reviewer: @sixers

Description:

No longer update lastUsed when firing the autofill shown pixel.

Steps to test this PR:

1. Open the background script devtools on the Network tab
2. With autofill enabled, open the tooltip on a page, for example https://privacy-test-pages.glitch.me/autofill/modal.html
3. Note the duck_address_last_used parameter (it should not be today)
4. Open the tooltip again. The parameter should stay the same
5. Now select an address
6. Open the tooltip again. The parameter should now be set to today

Automated tests:

• Unit tests
• Integration tests

Reviewer Checklist:

• Ensure the PR solves the problem
• Review every line of code
• Ensure the PR does no harm by testing the changes thoroughly
• Get help if you're uncomfortable with any of the above!
• Determine if there are any quick wins that improve the implementation

PR Author Checklist:

• Get advice or leverage existing code
• Agree on technical approach with reviewer (if the changes are nuanced)
• Ensure that there is a testing strategy (and documented non-automated tests)
• Ensure there is a documented monitoring strategy (if necessary)
• Consider systems implications

[GioSensation]

@jonathanKingston We need approval from someone with write access. By the way, can you give write access to @sixers so we can have faster loops in the future or should we go through IO?

The failing tests are also failing on main so they're not related.